Sludge pumping apparatus



Sept. 194.8. s. H. ERICSON 2,449,596

. SLUDGE PUMPING APPARATUS Filed Aug. 20, 1946 'INVENTOR.

5/6615 H. ER/CSON storage tanks of maritime vessels.

Patented Sept. 21, 1948 UNITED STATES PATENT" OFFlCE Appliea t lzffiiz t lz lszzf 2:212: 691,84l

5 Claims.

My invention relates to the art of pumpin heavy viscous oils and sludges over great elevations and for relatively long distances. The device shown is especially adaptable to the removal of the heavy sludges that collect inside the fuel describe my invention as it is applied to the cleaning of the fuel oil storage tanks of an oilburn'ing vessel.

In the length of time a heavy asphalt residue or sludge collects at the bottom of tanks where heavy bunker oils are stored. and as the sludge deposits accumulate. they will encroach more and more on the storage space of the fuel oil. Periodic cleaning is therefore necessary for all fuel oil storage tanks. Besides such periodic cleanings, it is often necessary on board a vessel to repair an accidental damage to the ship bottom, and as all such repair work is hot work" or welding and riveting, the tanks must'be thoroughly cleaned of oil and freed of the explosive gases that heavy fuel oils always generate when in contact with air.

As the nature of the oil sludges .precludes their handling ,by ordinary pumping methods, several special pumping methods have been devised for their pumping. The most successful sludge pumping is now performed by the so-calledwheeler vacuum system, which system has been installed in several of our leading ports. The subject matter of the Wheeler vacuum system is disclosed in the U. S. Patent No. 1,405,173. As shown and claimed in that patent, Wheeler uses heavy and cumbersome apparatus, which requires expensive floating equipment for its installation.

In the modern Wheeler sludge cleaning outfits, the sludge is pumped from the fuel tanks of the vessel to one of a pair of tanks mounted on the deck of the cleaning barge, while the other of the tanks is emptying its sludge contents into the storage space of the cleaning barge. This shift over from one vacuum tank to another requires frequent lapses in the pumping operation, for the capacity of the vacuum tanks is limited. Also, pumping is suspended during the period of time that it requires for the relatively large vacuum tanks to reestablish the high vacuum therein, required to operate such system.

One of the important features of my invention is to expedite the pumping of sludge from the fuel oil tanks of a ship by providing a relatively small vacuum receptacle, from which a conventional reciprocating pump continuously pumps the-viscous material, that has been drawn from the ships bottom, over the side thereof and deposited into like Olsson U. 5. Patent No. 1,858,682, employ con- 1 therefore tinuous conventional pumping from a small vacu um receptacle. but all such attempts have been unsuccessful where vacuum of more than 15 inches, as indicated on the mercury gauge, are used. Where oilyv sludges are pumped over the ship side a vacuum of some 22 inches mercury is required, and the pump primer of the Olsson device cannot be used.

Like Wheeler, I employ a high vacuum to raise the sludge over the ship side, while unlike Wheeler, I use a small vacuum receptacle from which a reciprocating pump continuously withdraws the pumped material.

Now, therefore, I have discovered, and-therein rests my claim to invention, that it is possible to use agconventional pump together with a small vacuum tank, ii the pump suction from the tank is placed low and is baffled of! from the upper part of the tank by means of a baiiie plate that is hermetically sealed at the top. I also prefer to provide a non-return by-pass from the pump suction to the upper part of the tank, in order to prevent accidental air binding of the pump.

However, other novel features of the invention will become apparent as the following specification is read in conjunction with the accompanying drawing.

In the drawing, Figure 1 is a diagrammatic cross-sectional view through an oil-burning vessel and an attend-ant sludge cleaning apparatus installed on the pier to which the vessel is moored.

Figure 2 is a cross-section of my preferred vacuum tank,Figure 3 is a plan view of the tank top, and Figure 4 is an enlarged detail vertical view of the intake nozzle.

Referring to the drawing in which like reference characters designate corresponding parts, i denotes an oil-burning vessel and t is my preferred vacuum tank into which the sludge ii that reposes in the double-bottom compartment l is to be pumped by my apparatus. My apparatus is composed of two distinct transmission lines, the vacuum transmission line 5 that is adapted to be slung over the ship side and reach into the doublebottom tank of the ship, and the pump-transmission line 8 through which the .pumped material is pumped to a convenient depository on shore by the discharge pump i. Mounted on shore is also a high vacuum pump 8, which connects to the top of tank 2 by means of pipe 9. I The pump suction i0 is shown connected to'the lower portion of the tank, and the by-pass line H connects the pump suction to the upper portion of the tank. In the by-pass line the non-return valve I2 is placed allowing passage from the pump suction to the tank top but not vice-versa. The baille plate I 3 ends at a substantial distance from the tank bottom, and is bent over at an-angle at top and welded to the tank shell, thus hermetically sealing compartment H in which the pump suction is located. A clean-out valve I5 is provided at the tank bottom for direct discharge into the sludge pit It.

The tank top is provided with two flanged pipe connections, the pipe connection H, which extends for a distance into the tank with its end preferably cut at a bias, and the pipe connection I 8. The connection I I serves the vacuum suction hose, and connection l8 serves the suction pipe of the high vacuum pump 8. Gauges I9 and 2d are shown provided in the tank top and the baffled-off tank compartment respectively.

An auxiliary steam service pipe 2| properly valved is also provided and intended for use when extremely viscous material is pumped, and also for blowing out the transmission lines when they become accidentally clogged.

At the end of the vacuum transmission hose, I prefer to provide an inlet nozzle 22 in the form of a pipe reducer, provided with an air inlet 23.

o It is to be noted that in my device all transmission lines are preferably 4 inches in diameter, the tank 30 inches in diameter and the vacuum pump has a volumetric displacement of some 500 cubic feet per minute.

The action of the sludge pumping apparatus is as follows:

The vacuum pump and the discharge pump are started and the end of the intake nozzle is inserted in the material to be pumped, care being taken not to submerge air inlet 23. The material is now being sucked up in a more or less broken up mass, which rushes through the hose and is violently discharged into the vacuum tank. The operation of the system, where heavy sludges are encountered, is distinctly intermittent, and great fluctuations on the vacuum gauges are observed. when a mass of material is sucked up at first into the hose, the hose becomes more and more sealed and the vacuum increases in the tank and the built-up sludge column in the suction hose snaps oil at the air inlet and moves as a unit through the suction hose and is discharged into the vacuum tank. When the sludge column discharges into the tank, and the air seal in the hose is broken, an instantaneous vacuum drop of some 6 inches mercury is observed on the gauge in the tank top. The vacuum usually fluctuates between 22 and 15 inches mercury in the tank top. During the low vacuum period, the attenuated air which is trapped in the bafliedof? tank compartment is compressed to some 12 inches mercury allowing for the liquid level difference of the tank compartments and the impact pressure of the sludge discharge. The liquid level in the baffled-oil compartment will then rise to the line 25, shown on the drawing. A moment later when a new sludge column is built up in the suction hose, the vacuum in the tank top increases, the trapped air inside the haiile will then expand and depress the liquid towards the pump suction until it reaches to line 25 close to the pump suction.

The pressure of the trapped air in thebailie space ll inside the upright tank 2 fluctuates between some 15 and 12 inches mercury with due consideration to the liquid level differential inside the tank compartments. When the vacuum grows inside the upper tank compartment, the air in the baflle compartment expands and g 4 presses the liquid material towards the pump suction, and a vacuum drop in the tank top translates itself into liquid pressure forcing the material into the bafile space and towards the pump suction.

The reciprocating pump, shown on the drawing, will therefore always work against a near constantsuction head approximating the lower vacuum fluctuation in the tank top and reduced by the liquid differential of the tank compartments.

It is also to be noted that a substantial amount of air is entrained in the sludge discharge into the tank and that quite a sizeable amount of air collects in the baited-off space of the tank .during pumping. In a short time, air will collect to such an extent that the lower liquid level in the bafie space will move so close to the pump suction that air will actually be sucked up by the pump. A main function of the non-return by-pass is therefore to prevent the sucked-up air from reaching the pump and interfere with the pumping. The described pump action is continuously repeated during the pumping operation.

Having thus described the invention, what I claim as new and desire to secure by Letters Patin the lower part of the tank hermetically sealed off from the upper part of the tank and means for creating a pump suction from the lower part of thebaiiie space inside the tank.

2. In an apparatus for pumping viscous material an upright vacuum tank, a suction transmission line connected to the upper part of the tank, a baifle space in the tank sealed from the upper part of the tank, means for creating a pump suction from the lower part of the baiile space and a non-return by-pass from said pump suction to the upper part of the tank.

3. Means for transferring viscous material continuously from the interior of a maritime vessel to an overside depository comprising means for creating a vacuum in an overside receptacle to suck such material to an elevation and deliver it directly into said receptacle, means for admitting air into the suction end of the transmitting line so as to cause vacuum variations in said receptacle, pump means for continuously pumping the material from the receptacle to the depository, and means for trapping air entrained in the pumped material at the pump suction to lower the vacuum therein.

4. An apparatus for pumping viscous material from the inside of a ship into an overside receptacle comprising in combination, an upright tank, a transmission line communicating with the upper part of said tank, means'for introduclng air into the inlet end of the transmission line, means for creating a vacuum in the tank to suck the material into the tank, a bafiie space in the tank hermetically sealed off from the tank and defined by an angle wall having its lower end spaced upwardly from the bottom of the tank between the side walls of the tank and its upper angle end secured to a side wall of the tank adjacent the upper end thereof and means upper part of the tank and defined by an angle wall having its lower end spaced upwardly from the bottom of the tank and between the side walls of the tank with its upper angle end secured to a side wall of the tank adjacent the upper end thereof, means for creating a pump suction from the lower end of the baflle space and a non-return by-pass from said pump suction to the upper part of the tank.

SIGGE H. ERICSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,858,682 Olsson May 17, 1932 2,089,691

Cross Aug. 10, 1937 

